Benin

Relief

Benin consists of five natural regions. The coastal region is low, flat, and sandy, backed by tidal marshes and lagoons. It is composed of, in effect, a long sandbar on which grow clumps of coconut palms; the lagoons are narrower in the western part of the country, where many have become marshes because of silting, and wider in the east, and some are interconnected. In the west the Grand-Popo Lagoon extends into neighbouring Togo, while in the east the Porto-Novo Lagoon provides a natural waterway to the port of Lagos, Nigeria, although its use is discouraged by the political boundary. Only at Grand-Popo and at Cotonou do the lagoons have outlets to the sea.

Behind the coastal region extends the barre country—the word being a French adaptation of the Portuguese word barro (“clay”). A fertile plateau, the barre region contains the Lama Marsh, a vast swampy area stretching from Abomey to Allada. The landscape is generally flat, although occasional hills occur, rising to about 1,300 feet (400 metres).

The Benin plateaus, four in number, are to be found in the environs of Abomey, Kétou, Aplahoué (or Parahoué), and Zagnanado. The plateaus consist of clays on a crystalline base. The Abomey, Aplahoué, and Zagnanado plateaus are from 300 to 750 feet high, and the Kétou plateau is up to 500 feet in height.

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The Atakora Mountains, in the northwest of the country, form a continuation of the Togo Mountains to the south. Running southwest to northeast and reaching an altitude of 2,103 feet (641 metres) at their highest point, they consist of a highly metamorphosed quartzite interior.

The Niger plains, in the northeast of Benin, slope down to the Niger River valley. They consist of clayey sandstones.

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Drainage

Apart from the Niger River, which, with its tributaries the Mékrou, Alibori, and Sota, drains the northeastern part of the country, the three principal rivers in Benin are the Mono, the Couffo, and the Ouémé. The Mono, which rises in Togo, forms the frontier between Togo and Benin near the coast. The Couffo, near which stands Abomey, flows southward from the Benin plateaus to drain into the coastal lagoons at Ahémé. The Ouémé rises in the Atakora Mountains and flows southward for 280 miles; near its mouth it divides into two branches, one draining to the east into Porto-Novo Lagoon and the other to the west into Nokoué Lake. The Atakora Mountains form a divide between the Volta and Niger basins.

Climate

Two climatic zones may be distinguished—a southern and a northern. The southern zone has an equatorial type of climate with four seasons—two wet and two dry. The principal rainy season occurs between mid-March and mid-July; the shorter dry season lasts to mid-September; the shorter rainy season lasts to mid-November; and the principal dry season lasts until the rains begin again in March. The amount of rain increases toward the east. Grand-Popo receives only about 32 inches (800 millimetres) a year, whereas Cotonou and Porto-Novo both receive approximately 50 inches. Temperatures are fairly constant, varying between about 72° and 93° F (22° and 34° C), and the relative humidity is often uncomfortably high.

In the northern climatic zone, there are only two seasons, one dry and one rainy. The rainy season lasts from May to September, with most of the rainfall occurring in August. Rainfall amounts to about 53 inches a year in the Atakora Mountains and in central Benin; farther north it diminishes to about 38 inches. In the dry season the harmattan, a hot, dry wind, blows from the northeast from December to March. Temperatures average about 80° F (27° C), but the temperature range varies considerably from day to night. In March, the hottest month, diurnal temperatures may rise to 110° F (43° C).